There is an image forming apparatus which conveys a sheet-like medium (hereinafter collectively referred to as a “sheet”) such as paper and the like, and meanwhile, forms an image on the sheet. The image forming apparatus is provided with an image forming section for forming a visible image (toner image) with toner and a fixing device for fixing a toner image on the sheet through heat and pressure. However, there is a possibility that it is hard to reduce the time required to switch a fixing condition such as a temperature when executing a plurality of different fixing operations according to the category of the toner and the like.